Degraders of the dengue virus capsid protein exhibit differentiated pharmacology relative to capsid inhibitors.

Due to the limited size of viral genomes, most viral proteins are multifunctional; yet most direct-acting antivirals are designed as single-function inhibitors. The dengue virus (DENV) capsid protein serves as a building block for new virions while also interacting with multiple host factors to remodel the cellular environment. Using established capsid inhibitor ST148 as a targeting ligand, we develop a DENV capsid degrader, RPG-01-132, that exhibits a broadened spectrum of activity against the four DENV serotypes and an ST148-resistant mutant virus. Using multiple approaches, we show that RPG-01-132's sub-micromolar antiviral activity is due to CRL4CRBN-dependent degradation of capsid and that this mechanism disrupts capsid-related pathways required for productive infection, including infectious virus output and capsid-mediated antagonism of the interferon response. This pharmacology is well-differentiated from ST148, which interferes with assembly of new virions, but has no demonstrated effect on the capsid's nonstructural functions. These findings demonstrate that targeted protein degradation can thus enable antiviral pharmacology not observed with conventional antiviral inhibitors and that is resilient to point mutations that reduce inhibitor potency.